1. Field of Endeavor
The present invention relates to a continuous-flow machine, in particular a turbine or a compressor.
2. Brief Description of the Related Art
A continuous-flow machine normally has at least one stator blade section which has a plurality of stator blades which are arranged alongside one another in a lateral direction running transversely with respect to the main flow direction of a working gas and project into a gas path of the working gas. Furthermore, an adjacent section can be adjacent to the rotor blade section, upstream or downstream in the main flow direction, and has a plurality of adjacent elements which are arranged alongside one another in the lateral direction and bound the working gas path at the side. A gap can be formed in the main flow direction between stator blades of the stator blade section and the adjacent elements of the adjacent section, which gap extends in the lateral direction and through which a cooling gas can be introduced into the working gas path.
In this case, the cooling gas is introduced into the gap in order to prevent or at least reduce any ingress of the hot working gas into the gap. The cooling gas must accordingly be introduced into the gap at a pressure which is at equal magnitude to or is greater than the pressure in the working gas path.
The pressure in the working gas path is subject to certain fluctuations. In particular, it is possible to observe that stagnation-point pressure waves can occur on leading edges of the stator blades during operation of the continuous-flow machine and propagate in the opposite direction to the main flow direction. Furthermore, wake pressure waves can form on trailing edges of the stator blades and propagate in the main flow direction. Where the stagnation-point pressure waves or the wake pressure waves strike the gap, increased pressures occur in the working gas. In order nevertheless to make it possible to prevent or reduce any ingress of working gas into the gap, the pressure of the cooling gas in the gap is increased accordingly. A relatively large amount of cooling gas is therefore necessary overall in order to reduce or to prevent any ingress of hot working gas into the respective gap. The greater the amount of cooling gas that enters the working gas path, the lower is the efficiency of the continuous-flow machine. There is therefore a need to reduce the amount of cooling gas required.